1. Field of the Invention
The present invention relates to methods of pipeline construction in arctic and subarctic regions and apparatus for carrying out those methods, and more particularly to methods of pipeline construction in arctic and subarctic regions in the employment of which pipeline sections many joints in length are fabricated by welding and tested with water as the testing medium during summer weather and then installed in the pipeline by making comparatively few joints under winter field conditions, with little or no ecological damage and at great savings in money, labor, equipment, and materials, with much earlier and more realistic completion dates and with much better labor relations both in the short run and the long run both with native employees and temporary immigrant employees, and apparatus for carrying out those methods.
2. Description of the Prior Art
The prior art methods of pipeline construction in arctic and subarctic regions as exemplified in the construction of the northern portion of the Trans-Alaska Pipeline, being as they are largely adaptations of techniques employed in the construction of pipelines at lower latitudes, involve extremely serious if not substantially insuperable difficulties which arise from the nature of the arctic and subarctic regions themselves and from the many requirements necessarily imposed by governmental authorities in order to protect the tundra and permafrost from damage which is presently believed to be irreversible, and the long-run effects of which upon not only the native arctic and subarctic fauna and flora but the climate and perhaps the fauna and flora of the entire Northern Hemisphere, or the entire world, is very largely unpredictable, but is viewed with great gravity by those having the best information on the subject.
As is well-known to those having broad knowledge of the arctic and subarctic regions, the areas of tundra and permafrost over which the aforementioned difficulties obtain extend throughout virtually the entire coastal area of the Arctic Ocean, including not only the Alaskan North Slope region and the Far North region of Canada, but also the extensive arctic coastal regions of the USSR, and also extend many hundreds of miles to the south of those arctic coastal regions. For instance, the southern fringe of discontinuous permafrost extends below 62.degree. North Latitude near the Great Slave Lake. Further, the southern fringe of continuous permafrost lies well below the MacKenzie Delta, and thus, e.g., the 200-mile Alaska-Canada coastal section of the proposed Canadian Arctic Gas Pipeline lies entirely in the continuous permafrost zone. The proposed Polar Gas Pipeline extends to Melville Island, at a point above 75.degree. North Latitude, and thus almost 50% of this proposed pipeline lies in regions of continuous or discontinuous permafrost.
Due to governmental regulations necessitated by these characteristics of the arctic and subarctic ecostructure, which often are and will more often in the future be stringently enforced by government inspectors and others concerned with the protection of the arctic and subarctic ecostructure, many extremely if not prohibitively expensive measures must be taken if pipeline construction in summer in these regions is to be permitted at all. The most costly of these measures is the provision of a "work pad" of insulating gravel which is often required to be a least 4 feet deep and must be laid to considerable width, e.g., 100 feet or more, all along the pipeline right-of-way and wherever else construction activities and the movement of heavy equipment is to take place. In many regions of the arctic and subarctic sufficient quantities of native gravel for the construction of the many necessary miles of "work pads" is simply not available, and even where such quantities of gravel appear to be potentially available, as along the coastlines, a serious question arises as to the ecological damage which might be occasioned by the removal of this naturally-occurring gravel, such that a substantial possibility exists that subsequent governmental regulation will forbid its removal from its site of natural occurrence. Thus, considerable percentages of the necessary gravel for such "work pads" would necessarily have to be supplied by crushing rock excavated at locations lying at considerable distances, e.g., 20 miles, from the sites of the required "work pads", thus necessitating the construction of further "work pads" over which to transport the crushed gravel, as well as whatever is available of naturally-occurring gravel "borrow" to the nearest points of the "work pads".
When it is considered that one mile of such a gravel "work pad", including the cost of gravel and the cost of gravel-laying labor, may be as much as $1,800,000.00, and it is kept in mind that the present estimated prices of gasoline refined from petroleum transported through the Trans-Alaska Pipeline are already raising considerably unfavorable public reaction, it is not difficult to understand that in the future the summer construction of pipelines in arctic and subarctic regions employing the now conventional methods used in constructing the northern portion of the Trans-Alaska Pipeline may be regarded as totally economically infeasible.
A worse problem yet is that in summer pipeline ditches (in permafrost) can be kept open for only very limited times. When this problem is compounded by pipe failures and the like the entire schedule of a complete pipeline may fall one or two years into arrears.
In addition to the substantially insuperable problems and costs raised by ecology-preserving governmental regulations in arctic and subarctic areas, there are also vast areas of the arctic and subarctic in which the nature of the terrain itself serves as a virtually insuperable barrier to summer pipeline construction. These areas are laced with rivers, lakes and other water barriers which prevent the passage of heavy equipment, and thus prevent the transport of pipe joints, sideboom tractors, tow tractors, welding equipment, pipe-bending equipment, pipe-wrapping equipment, etc., and the many other types of equipment and supplies which are indispensible to the construction of pipelines according to conventional methods, even where sufficient gravel is available for the construction of "work pads" of sufficient size over the intermediate areas of "dry land".
For the above reasons, and many others not discussed in detail, pipeline construction in arctic and subarctic regions is forced into the winter period throughout those areas of permafrost and tundra over which or through which pipelines must be constructed if the vast fossil fuel resources of the arctic and subarctic regions are to be brought to the lower latitudes for consumption.
One of the expedients which makes arctic and subarctic winter pipeline construction possible is the use of work pads made from compacted snow, rather than gravel. These elongated snow pads, sometimes called "snow roads", rather than "work pads", are not necessarily fabricated from naturally-occurring snow but rather may be fabricated and have been fabricated in the prior art from "artificial snow" made by portable or self-propelled snow-making machines from water trucked in in heated tanker trucks. Such snow-making machines, which are well-known in the prior art and are commercially available, can produce sufficient artificial snow in one day to form a compacted snow pad 2 feet deep by 30 feet wide and 1 mile long.
Since such a snow pad may, in accordance with the conventional method, have to be 100 feet wide or more to give maximum productivity or construction, it may be necessary to employ several of such snow-making machines in order to advance the necessary snow pad with sufficient rapidity to accommodate the requirements of arctic and subarctic winter pipeline construction, particularly since "winter", for working purposes, is defined by governmental authorities as extending from the first day to the last day on which a particular degree of frost penetration has occurred. Work may be interrupted by early thaw at the end of the season, after which work, even as carried on by low ground-pressure vehicles, must be suspended.
This requirement for multiple snow-making machines, each of which may typically cost $1,000,000.00, along with the great expense of trucking in constantly heated water when the ambient temperature may be as low as 40 below zero Fahrenheit (-40.degree. F.), results in the cost of a typical snow pad 120 feet wide and 2 feet thick being as much as $290,000.00 per mile. Further, these snow pads may have in one winter of construction following now conventional methods a linear extent of, e.g., 630 miles along the pipeline right-of-way alone, not to mention the additional miles of somewhat narrower snow pad which must be constructed in order to haul supplies to the right-of-way, etc.
The cost of providing a 120-foot wide snow pad 600 or more miles long each winter is one of the largest but by no means the only economic problem involved in the construction of pipelines in arctic and subarctic winters.
Another such economic problem springs from the virtually absolute requirement that all construction equipment be operated 24 hours of every working day. When such a piece of equipment has stood unoperated for only a short length of time in the out-of-doors in arctic and subarctic winters and its temperature has dropped to the normal ambient of somewhere between -25.degree. and -40.degree. F. it cannot be restarted, except after complete thawing by the application of heat from heat sources requiring quantities of, e.g., propane which are economically unavailable at winter arctic and subarctic pipeline construction sites.
As learned in the construction of the Trans-Alaska Pipeline, heavy equipment operated for several months on a constant 24 hour per day basis must be brought out at the end of that period and completely rebuilt, including the complete teardown of the equipment and the replacement of virtually all bearings and mutually moving contacting surfaces, such as piston rings. Typically, a sideboom tractor may cost as much as $250,000.00, and may have to be rebuilt at a cost equal to 30% or more of its original price after a winter of continuous, 24 hour per working day operation, if indeed it lasts through the working winter. Even with a costly summer overhaul the value of a $250,000.00 sideboom tractor after two arctic or subarctic winters can be as low as scrap value. Additionally, the provision of human resources by way of labor for arctic and subarctic winter pipeline construction in accordance with the now conventional methods employed in the construction of the northern reaches of the Trans-Alaska Pipeline presents another almost insurmountable problem, especially since the arctic and subarctic winters as defined by governmental authorities, which as explained above is the only work period practically available, may be as short as 100 days per year, or even 85 days per year. In addition, the wind chill factor may shut down work even when the temperature is not severely low.
This extremely short work season may require the hiring of as many as 15,000 men and women to work in the out-of-doors in the extremely harsh arctic and subarctic winters and to be confined to the work area between work shifts for many weeks at a time.
Even putting aside the unprecedented labor cost in this situation and the greatly reduced efficiency of the individual worker working under such extremely adverse conditions (estimated by some to be as much as 30% below summer work level efficiency) and the concomitant labor relations problems of a new and unprecedented order due to the adverse psychological effects of virtual confinement of the workers at the work site during off-work hours and in "survival shacks" during work hours, experts in the arctic and subarctic pipeline construction art are becoming more and more aware of the possibility that sufficient labor willing to work in the outdoors under arctic and subarctic winter conditions over the required timespans may simply not be available at all. This is particularly true when the type of labor in question is, for instance, the highly expert arc welders necessary to fabricate high-quality, leakproof welds in the field under such conditions.
Over and beyond these problems raised by the necessity to provide great numbers of workers in the field in arctic and subarctic winters is the recognized fact that such workers not only are inefficient under such conditions, as just explained, but also tend to frequently produce a defective work product, simply due to the psychological pressures of the harsh environment, and not to labor "slowdown" tactics or intentional sabotage.
It is recognized by experts in this art that, cumulatively, these problems of pipeline construction under arctic and subarctic winter conditions can result in the need for an extra year or more of construction time, which requirement can be or become a nationally important concern due to the size of the cost overrun which may amount to billions of dollars.
It has also been projected that the abovementioned labor problems may in the near future be seriously exacerbated by governmental regulation inspired by concern for native employees, and the concomitant demand that those native employees be given substantially regular employment rather than seasonal employment amounting to 100 days or less per year.
Further, the problems of arctic and subarctic winter construction detailed immediately hereinabove apply not only to the construction of the pipeline itself but also apply to the construction of auxiliary facilities and structures, sometimes called "civils", such as compressor or pump stations, foundations, access roads from river wharves, airstrips for heavy aircraft (Hercules), airstrips for lighter service aircraft, campsites, stockpiles, wharves, warehouses, etc.
Many further problems are, of course, raised by conventional arctic and subarctic winter pipeline construction methods, and arctic and subarctic winter conditions. For example, the inspecting of weld joints hydrostatically at, say, 1400 psi under conditions wherein water simply cannot be used for such testing require the provision, storing, pressurization, etc., of large volumes of methanol, or other "anti-freeze" fluids. This problem is, of course, very greatly exacerbated by the present, or in some countries very near future, requirement that no such "foreign" materials be discharged into the arctic or subarctic environment either advertently or inadvertently. The equipment and methods mandated for the prevention of spillage of such "foreign" material will be seen to grossly exacerbate the abovementioned economic problems of arctic and subarctic winter pipeline construction.
Added to all of the above problems of arctic and subarctic winter pipeline construction, and perhaps surmounting them all in difficulty, if not impossibility, of solution is what might be called the "credibility problem". By this is meant the fact that the cumulative effect of unpredictable variations in the length of the "official" arctic and subarctic winters, unpredictable variations in labor costs, unpredictable variations in the cost of equipment and supplies due to continuing world-wide inflation, and unpredictable new costs resulting from the constant proliferation of ever more stringent government regulations designed to protect the arctic and subarctic ecosystem make the reliability of pipeline cost projections highly suspect, or hedged with such prestated broad limits of variation as to be virtually meaningless. This credibility problem, known to have already resulted in billions of dollars of cost overruns in earlier arctic and subarctic winter pipeline construction efforts, has resulted in the refusal of governments to grant permits for such construction, which refusals are now delaying the construction of many hundreds of miles of key arctic and subarctic pipeline, as well as the virtual unavailability or extreme high cost of venture capital for the construction of pipelines in these regions. Further, it is almost uniformly projected by those knowledgeable in the problems of pipeline construction in these regions that this credibility problem will be greatly exacerbated in the near future by additional problems of inflation, governmental regulation, etc.
While it is true that many measures and expedients have been suggested and adopted for ameliorating in some slight degree the cost and credibility problems of arctic and subarctic pipeline construction no broad and all-embracing "quantum leaps" in arctic and subarctic pipeline construction methods and apparatus have to the present data resulted in any substantial reduction in the above-detailed cost problems or in the elimination of the above-defined credibility problem.
Among these stop-gap methods and expedients are the welding together of two or three pipe joints before laying in order to save welding at the place of installation. These two and three-joint pipe sections are strung along the pipeline right-of-way behind the snow-making machines which lay the required snow pad, interspersed with a certain percentage of single joints which must be bent on site by bending machines under arctic and subarctic winter conditions. While such "double-jointing" and "triple-jointing" results in some savings in welding costs and employment problems, etc., this sub-method does not either sufficiently reduce the huge cost of arctic and subarctic winter pipeline construction to result in lowering the cost of the necessary venture capital or contribute substantially to the solution of the credibility problem.
As is well-known, each weld joint produced in the field, involving a great deal of very costly pre-heating by propane burners or the like to avoid weld cracking and other quality problems, also involves a very substantial possibility of weld defects even in the hands of the most expert pipeline welders, and extensive repairs of these defects can ruin an arctic or subarctic pipeline construction schedule if the making of all such repairs is strictly enforced. This situation, along with the great psychological problems of working in arctic and subarctic winters at all, has at times in the past led to the attempted concealment of such defects and the avoidance of such costly repairs. Such concealment, cumulated over an entire winter period, and perhaps even lying over into a second winter period, when subsequently discovered, can result in cost overruns of many tens of millions of dollars for correction. This kind of statistical and projectional unreliability results in extremely high cost rates for working capital, if indeed such working capital is available at all for future arctic and subarctic winter pipeline construction projects.